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Dates: during 1980-1989
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...sandstone interleaved with volcanic basalt, date from between 225 million and 175 million years ago. The entire rock formation was long thought to be virtually devoid of fossils and thus of little interest to paleontologists. In fact, says Neil Shubin, 25, a graduate student in biology at Harvard, the site they discovered "looks like Rocky Road ice cream. It's dark rock absolutely splattered with bone." Says his partner, Geologist Paul Olsen, 32, of Columbia's Lamont-Doherty Geological Observatory: "We were shocked by the number of fossils...
Excavations at the Nova Scotia site have so far yielded more than 100,000 fossilized bone fragments, all dating from shortly after the mass extinction some 200 million years ago that marked the end of the Triassic period and the beginning of the Jurassic. Because of some rapid change, perhaps a catastrophic event, the fossil record shows, 43% of the animal families whose fossilized remains are found in the older Triassic rock are missing from the Jurassic layers just above it. The sudden mass extinction opened the evolutionary way for the proliferation of the dinosaurs and the emergence...
Around the time of the mass extinction, the fossil site was apparently in a 300-mile-long rift valley fringed with high mountains. The climate swung between wet and dry spells every 20,000 years or so, leaving telltale alternating layers of lake sediments and sandstone visible on the present-day cliffs. "When it rained," says Olsen, "chunks of rock and mud raced down the mountainsides and buried large swaths of ground." Many of the now fossilized animals escaped the slides, only to be trapped in cracks that opened as the mud flow dried and shrank. Olsen believes the animals...
Mark Anders, 38, a Berkeley graduate student who works with the Alvarez team, is methodically examining rock samples from the Nova Scotia site, looking for evidence of shocked quartz--grains with their normal crystalline pattern distorted by the kind of shock wave the Manicouagan impact would have produced. If he finds the mineral clues below the fossil deposits, he says, the impact probably preceded and could have caused the extinction, thus strengthening the Alvarez hypothesis...
...Commerce, beaming at a line of 50 Fibercraft job applicants last week. "For the first time in ages, people are talking positively. We've finally got something going in this town." Fibercraft comes at a price, measured on a gigantic red United Way-style thermometer at Main and Fifth, site of the town's only traffic light. To persuade the company to move to Sac City, town developers, in addition to supplying free manufacturing space, promised to pay its moving expenses from Minnesota, finance equipment and even supply some operating capital. The total: $175,000. As of last week...